The present invention relates to a fuel device for a fuel supply system of an internal combustion engine of a motor vehicle.
Such a filter device is disclosed for example in U.S. Pat. No. 5,078,167. This filter device has a housing, in which a filter insert is arranged. The filter device has a dirt-side supply from a fuel supply container of the motor vehicle and a clean-side outlet to the internal combustion engine. Moreover the filter device has a return leading from the dirt side to the fuel supply container, which is controlled by a valve device. The valve device has a movable wall which is loaded with the fuel pressure at the clean side of the filter device and formed as a diaphragm. The valve device holds the return closed until the fuel pressure at the clean side exceeds a predetermined value, and thereby the diaphragm is deformed and the return is released.
The valve device has an expensive construction with a valve seat movable by the diaphragm. Moreover, the valve device is flanged transversely to the housing of the filter device and requires a great mounting space. The construction and the mounting space of the filter device is negatively influenced by the valve device.
Accordingly, it is an object of present invention to provide a filter device of the above mentioned general type, which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a filter device for a fuel supply system of an internal combustion engine of a motor vehicle, in which the valve device has a rod which is displaceable by the movable wall and extends through the filter insert from the clear side to the dirt side and controls with its end region the return at the dirt side.
When the filter device is designed in accordance with the present invention, the construction of the valve device is simplified and moreover the mounting space is reduced, so that the filter device can be produced correspondingly simpler and with less space.
In accordance with another feature of the present invention the end region of the rod is formed as a sealing surface and cooperates with a valve seat which surrounds an opening of the return. It involves an especially simple construction of the valve device for the small separate valve member.
In accordance with another feature of the present invention, the filter device has a heating device arranged at the dirt side. This prevents loading of the filter insert at low temperatures. Thereby the heating device has to be designed only for the actual fuel quantity passing through the filter insert.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.